Post by Steady Micro Aggressor on Feb 20, 2007 0:01:19 GMT -5
by Patrick J. Michaels
The United Nations Intergovernmental Panel on Climate Change released a slim summary last Friday trimming down thousands of pages of its massive overall Fourth Scientific Assessment on global warming, which will be released in May.
Hopefully the "Summary for Policymakers" will be an accurate distillation. Hundreds of scientists have been involved in the review process, and it's safe to say that means hundreds of bored scientists, because there's very little in it that's scientifically new. For example, it will report with increasing certitude that humans are responsible for most of the surface warming that began in the mid-1970s. That's been pretty obvious for years.
Graphs in Friday's summary will show that the rate of global warming has been remarkably constant -- about 0.18°C per decade -- since 1975. So, any news report that "UN panel says the planet is warming at an increasing rate" (and there will be many) will be dead wrong.
For over a century, it has been known that increasing the atmospheric concentration of carbon dioxide will eventually lead to a warming of surface temperatures, concentrated more in winter than summer, and more in mid and high-latitudes over land. That's exactly what's been observed for years, as is a global cooling of the stratosphere, another prediction of greenhouse theory.
More interesting, and, again, less newsy, is that the communal behavior of the dozens of computer models for future climate also predicts a constant (rather than an increasing) rate of warming.
That means that unless the collective conclusions of all of the models is wrong, we can confidently estimate a warming of about 1.8°C from 2000 to 2100. That's very near the low end of the range of projections released on Friday. The fact that the most logical distillation of observed and predicted warming yields such a modest heating should be reassuring, rather than alarming.
The new estimate for maximum rise in sea level, assuming a middle-of-the-road estimate for carbon dioxide changes, is going to be lower than in previous IPCC reports. The last figure I saw was around 17 inches by 2100, down 40% from their previously estimated maximum.
A small but very vocal band of extremists have been hawking a doomsday scenario, in which Greenland suddenly melts, raising sea levels 12 feet or more by 2100. While this forecast enjoys no real support in the traditionally-refereed scientific literature, it is repeated everywhere, and its supporters are already claiming that the IPCC -- the self-proclaimed "consensus of scientists" -- is now wrong because it has toned down its projections of doom and gloom.
But the integrated warming of southern Greenland (the region that sheds ice) was much greater for several decades in the early and mid-20th century than in the last decade. In fact, with the exception of one year (2003), Greenland's recent temperatures aren't particularly unusual, nor is its rate of ice loss.
As measured recently by satellite, and published in Science magazine, Greenland is losing .0004% of its ice per year, or 0.4% per century. All modern computer models require nearly 1000 years of carbon concentrations three times what they are today to melt the majority of Greenland's ice. Does anyone seriously believe we will be a fossil-fuel powered society in, say, the year 2500?
In summary, what's not new in today's IPCC report -- that humans are warming the planet -- will be treated as big news, while what is new -- that sea levels are not likely to rise as much as previously predicted -- will be ignored, at least by everyone except the extremist fringe.
www.cato.org/pub_display.php?pub_id=7543
The United Nations Intergovernmental Panel on Climate Change released a slim summary last Friday trimming down thousands of pages of its massive overall Fourth Scientific Assessment on global warming, which will be released in May.
Hopefully the "Summary for Policymakers" will be an accurate distillation. Hundreds of scientists have been involved in the review process, and it's safe to say that means hundreds of bored scientists, because there's very little in it that's scientifically new. For example, it will report with increasing certitude that humans are responsible for most of the surface warming that began in the mid-1970s. That's been pretty obvious for years.
Graphs in Friday's summary will show that the rate of global warming has been remarkably constant -- about 0.18°C per decade -- since 1975. So, any news report that "UN panel says the planet is warming at an increasing rate" (and there will be many) will be dead wrong.
For over a century, it has been known that increasing the atmospheric concentration of carbon dioxide will eventually lead to a warming of surface temperatures, concentrated more in winter than summer, and more in mid and high-latitudes over land. That's exactly what's been observed for years, as is a global cooling of the stratosphere, another prediction of greenhouse theory.
More interesting, and, again, less newsy, is that the communal behavior of the dozens of computer models for future climate also predicts a constant (rather than an increasing) rate of warming.
That means that unless the collective conclusions of all of the models is wrong, we can confidently estimate a warming of about 1.8°C from 2000 to 2100. That's very near the low end of the range of projections released on Friday. The fact that the most logical distillation of observed and predicted warming yields such a modest heating should be reassuring, rather than alarming.
The new estimate for maximum rise in sea level, assuming a middle-of-the-road estimate for carbon dioxide changes, is going to be lower than in previous IPCC reports. The last figure I saw was around 17 inches by 2100, down 40% from their previously estimated maximum.
A small but very vocal band of extremists have been hawking a doomsday scenario, in which Greenland suddenly melts, raising sea levels 12 feet or more by 2100. While this forecast enjoys no real support in the traditionally-refereed scientific literature, it is repeated everywhere, and its supporters are already claiming that the IPCC -- the self-proclaimed "consensus of scientists" -- is now wrong because it has toned down its projections of doom and gloom.
But the integrated warming of southern Greenland (the region that sheds ice) was much greater for several decades in the early and mid-20th century than in the last decade. In fact, with the exception of one year (2003), Greenland's recent temperatures aren't particularly unusual, nor is its rate of ice loss.
As measured recently by satellite, and published in Science magazine, Greenland is losing .0004% of its ice per year, or 0.4% per century. All modern computer models require nearly 1000 years of carbon concentrations three times what they are today to melt the majority of Greenland's ice. Does anyone seriously believe we will be a fossil-fuel powered society in, say, the year 2500?
In summary, what's not new in today's IPCC report -- that humans are warming the planet -- will be treated as big news, while what is new -- that sea levels are not likely to rise as much as previously predicted -- will be ignored, at least by everyone except the extremist fringe.
www.cato.org/pub_display.php?pub_id=7543